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Background The Silk Vista Baby (SVB, BALT) is a first-in-class flow-diverter device delivered using a 0.017” microcatheter, designed for the treatment of intracranial aneurysms, including those in small diameter vessels. This study reports a systematic literature review (SLR) to evaluate the safety and efficacy of using SVB to treat intracranial aneurysms in vessels less than 3.5 mm in diameter.Methods We performed a PRISMA-compliant SLR to evaluate the outcomes of SVB in the treatment of aneurysms in small intracranial vessels. Primary outcomes were occlusion status and major stroke, and secondary outcomes included all-cause mortality, procedure-related neurologic death, and post-operative aneurysm rupture. Data were expressed as descriptive statistics only.Results A total of four studies, including 163 patients with 173 intracranial aneurysms, were included. The most common aneurysm locations were the anterior cerebral artery (24.9% [43/173]), the middle cerebral artery (24.3% [42/173]), and the anterior communicating artery (23.1% [40/173]). Parent artery diameter ranged from 0.9 mm to 3.6 mm, and 29% were acutely or previously ruptured aneurysms. Overall, complete or near-complete occlusion was 72.1% on early-term follow-up. Mortality rate among the studies was 2.5%, with 3 instances adjudicated as neurologic deaths (1.8%). Major stroke was noted in 1.2% of cases, and branch occlusion or stent thrombus formation in 5.5%.Conclusion Our review suggests that SVB is a safe and effective treatment for intracranial aneurysms in small vessels. Further prospective and comparative studies with patient outcome data specific to aneurysm location are needed to confirm the safety and efficacy of SVB.

Background Advancements in flow diversion technology have revolutionized the treatment of intracranial aneurysms. The pipeline embolization device (PED) and the flow redirection endoluminal device (FRED) have emerged as prominent tools in this field. This study aims to compare the safety and efficacy profiles of PED and FRED in the treatment of intracranial aneurysms.Methods Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive literature search was conducted across PubMed, Web of Science, and Scopus databases. Studies comparing PED and FRED were included and data extraction focused on study characteristics, patient demographics, and clinical and radiological outcomes. Primary outcomes were favorable outcomes, described as modified Rankin scale (mRS) 0–2 score, and complete/near-complete occlusion, while secondary outcomes included retreatment rate and thromboembolic and hemorrhagic complications.Results Five studies, comprising 1238 patients, were included. No significant differences were found between PED and FRED in terms of complete occlusion at 6 months and 1 year, complete/near-complete occlusion at the last follow up, retreatment rates, and thromboembolic, in-stent thrombosis and hemorrhagic complications. However, FRED was significantly associated with higher favorable outcomes compared to PED (odds ratio: 0.37; confidence interval: 0.17 to 0.81; p = 0.01).Conclusion This study showed that both PED and FRED had comparable rates of complete occlusion, retreatment and complications, and FRED also demonstrated a higher likelihood of achieving favorable outcomes. The study underscores the need for further research with larger cohorts and longer follow up to consolidate these findings.

Background Endovascular treatment with the woven endobridge (WEB) device has been widely utilized for managing intracranial aneurysms. However, predicting the probability of achieving adequate occlusion (Raymond–Roy classification 1 or 2) remains challenging.Objective Our study sought to develop and validate a predictive calculator for adequate occlusion using the WEB device via data from a large multi-institutional retrospective cohort.Methods We used data from the WorldWide WEB Consortium, encompassing 356 patients from 30 centers across North America, South America, and Europe. Bivariate and multivariate regression analyses were performed on a variety of demographic and clinical factors, from which predictive factors were selected. Calibration and validation were conducted, with variance inflation factor (VIF) parameters checked for collinearity.Results A total of 356 patients were included: 124 (34.8%) were male, 108 (30.3%) were elderly (≥65 years), and 118 (33.1%) were current smokers. Mean maximum aneurysm diameter was 7.09 mm (SD 2.71), with 112 (31.5%) having a daughter sac. In the multivariate regression, increasing aneurysm neck size (OR 0.706 [95% CI: 0.535–0.929], p= 0.13) and partial aneurysm thrombosis (OR 0.135 [95% CI: 0.024–0.681], p= 0.016) were found to be the only statistically significant variables associated with poorer likelihood of achieving occlusion. The predictive calculator shows a c-statistic of 0.744. Hosmer–Lemeshow goodness-of-fit test indicated a satisfactory model fit with a p-value of 0.431. The calculator is available at: https://neurodx.shinyapps.io/WEBDEVICE/.Conclusion The predictive calculator offers a substantial contribution to the clinical toolkit for estimating the likelihood of adequate intracranial aneurysm occlusion by WEB device embolization.

Objective Carotid artery webs are an underappreciated cause of recurrent ischemic stroke, and may represent a significant portion of cryptogenic stroke. Evidence-based guidelines for the management of symptomatic carotid webs do not exist. The goal of this study is to audit our local experience for patients with symptomatic carotid artery webs undergoing carotid stenting as a treatment option, along with describing the hypothesized dynamic physiology of carotid webs.Methods All patients undergoing stenting for symptomatic carotid artery web at two comprehensive regional stroke centers with high endovascular thrombectomy volume from January 1, 2012 to March 1, 2021 were included. The modified Rankin Scale (mRS) score was used to define functional outcome at 3 months after stenting.Results Fourteen consecutive patients with symptomatic carotid artery webs underwent stenting. Twelve patients were female (86%), with a median age of 54 (IQR, 48–64) years across all patients. Stroke was the qualifying event in 12 (86%) patients and TIA in 2. Eleven patients (11/14, 79%) achieved a mRS score of 0–2 at 90 days, 2 (14%) were mRS 3–5, and one patient was lost to follow-up. The median follow-up was 12 months (IQR, 10–12). There was no recurrent stroke or TIA like symptoms in any patients.Conclusions Carotid stenting appears to be safe at preventing recurrent stroke/TIA with a median follow-up of 12 months in this retrospective multicenter observational study.

Purpose Pulsatile tinnitus can be caused by a high-riding jugular bulb (HRJB), characterized by the superior position of the jugular bulb in the petrous temporal bone. The anatomical position and morphology of this entity make it challenging for endovascular treatment. We report our experience with two patients successfully treated with a stent-assisted Woven EndoBridge (WEB; Microvention, Tustin, CA, USA) device.Materials and Methods We describe two cases of HRJB in patients presenting with disabling pulsatile tinnitus. Temporary balloon occlusion of the jugular bulb prior to the intervention reduced tinnitus intensity. Both patients were subsequently treated under general anesthesia with the WEB device deployed in the HRJB which was held by a stent deployed in the sigmoid sinus.Results Both procedures were successful with good positioning of the WEB device and no procedural complications. Both patients had complete resolution of pulsatile tinnitus immediately after the procedure. Follow-up imaging showed successful occlusion of the venous cavity with a widely patent stent.Conclusion Among patients with pulsatile tinnitus caused by an ipsilateral HRJB, a stent-assisted WEB device seems to be a viable endovascular option with angiographic and clinical success.

We describe a case of a 22-year-old man with a traumatic occipital artery pseudoaneurysm revealed by a painful expanding neck hematoma after a penetrating knife injury. A neuroendovascular consultation was requested after a computed tomography angiogram showed active pseudoaneurysm bleeding. Anatomical considerations of the upper cervical region including dangerous anastomosis between the vertebral and internal carotid artery are discussed, illustrating how this impacted our treatment strategy. We also discuss other treatment modalities after a thorough literature review of traumatic occipital artery pseudoaneurysms.

Flow diverters (FD) have become increasingly useful in treating complex intracranial aneurysms, particularly wide-necked and recurrent aneurysms. Their use has progressively expanded to smaller vessels beyond the circle of Willis (CoW), and Silk Vista Baby (SVB) is one such low-profile FD which stands out because of deliverability through a 0.017″ microcatheter and smoother navigability. Precise deployment of SVB, specifically, the proximal end, can be challenging in certain anatomical locations when the proximal landing zone is very short, limited by vessel bifurcation or important branches arising from the artery or its geometry. We present our series to describe our technique and rule to ‘PREDICT’ the final deployment of SVB in real time, and discuss the nuances, exceptions and bail-out strategies. Using this technique, we were able to precisely deploy SVB in distal intracranial vessels with a mean proximal landing zone as short as 2.6 mm in 80% instances, requiring bail-out strategies in only 20% cases. This rule can be reliably followed in treating complex intracranial aneurysms with SVB FD within a confined territory, until validated software-based real-time planning tools are developed.

Background Intra-procedural characterization of stroke thromboemboli might guide mechanical thrombectomy (MT) device choice to improve recanalization rates. Electrochemical impedance spectroscopy (EIS) has been used to characterize various biological tissues in real time but has not been used in thrombus.Objective To perform a feasibility study of EIS analysis of thrombi retrieved by MT to evaluate: (1) the ability of EIS and machine learning to predict red blood cell (RBC) percentage content of thrombi and (2) to classify the thrombi as “RBC-rich” or “RBC-poor” based on a range of cutoff values of RBC.Methods ClotbasePilot was a multicentric, international, prospective feasibility study. Retrieved thrombi underwent histological analysis to identify proportions of RBC and other components. EIS results were analyzed with machine learning. Linear regression was used to evaluate the correlation between the histology and EIS. Sensitivity and specificity of the model to classify the thrombus as RBC-rich or RBC-poor were also evaluated.Results Among 514 MT,179 thrombi were included for EIS and histological analysis. The mean composition in RBC of the thrombi was 36% ± 24. Good correlation between the impedance-based prediction and histology was achieved (slope of 0.9, R2=  0.53, Pearson coefficient  =  0.72). Depending on the chosen cutoff, ranging from 20 to 60% of RBC, the calculated sensitivity for classification of thrombi ranged from 77 to 85% and the specificity from 72 to 88%.Conclusion Combination of EIS and machine learning can reliably predict the RBC composition of retrieved ex vivo AIS thrombi and then classify them into groups according to their RBC composition with good sensitivity and specificity.

Background Neurointerventionalists use in-vitro vascular models to train for worst-case scenarios and test new devices in a simulated use environment to predict clinical performance. According to the Food and Drug Administration (FDA), any neurovascular navigation device should be able to successfully navigate two 360-degree turns and two 180-degree turns at the distal portion of the anatomical model. Here, we present a device benchmarking vascular model that complies with FDA recommendations.Methods Our vascular model was assembled from quantitative characterization of 49 patients who underwent CT angiography either for acute ischemic stroke caused by large vessel occlusion or for aneurysm treatment. Following complete characterization of these data, the vascular segments were 3D reconstructed from CT angiograms of 6 selected patients that presented with challenging anatomy. The curvature and total rotational angle were calculated for each segment and the anatomical parts that complied with FDA recommendations were fused together into a single in-vitro model.Results The model was constructed containing two common carotid branches arising from a type two aortic arch and the dimensions of the overall model exceeded the recommendations of the FDA. Two experienced neurointerventionalists tested the model for navigation difficulty using several devices on an in-vitro perfusion system and concluded that the model provided a realistic, challenging scenario.Conclusions This model provides a first prototype designed according to FDA recommendations of cumulative angle while also integrating an aggregation of actual patient-specific anatomy. The availability of this clinically relevant benchmark model presents a potential standardized approach for neurovascular device testing.

Background Pulsatile tinnitus (PT) can have huge impact on the patients’ quality of life and can be associated with curable vascular anomalies. In the present study, we aim firstly to describe our protocol for venous BTO and secondly to report possible predictors for a positive BTO test.Methods All consecutive PT patients undergoing BTO for the purpose of determining eligibility for venous neuro-intervention were included. We recommend BTO for patients when there is uncertainty in the association of the venous pathology identified on non-invasive cross-sectional imaging (CTV or MRV) and the patient's symptoms.Results Between May 2016 and October 2022, we recorded 29 venous balloon test occlusions fulfilling our inclusions criteria. Over the 29 procedures scheduled, 8 finally did not lead to a successful balloon test occlusion. The main reason was that the patient did not hear the PT on the day the angiogram was performed. Two patients could not have the BTO due to difficulties in venous navigation. After BTO, only four patients of our cohort were scheduled for an endovascular treatment.Conclusion We describe a technique and present a single cohort of venous BTO in severe PT patients with unclear anatomical cause. This angiographic test was useful to exclude patients from endovascular surgery and discuss the most probable cause of the PT. Complexity of vascular PT should support a patient-based approach when discussing interventional treatment.

Background and purpose Recent studies suggest that thrombus imaging characteristics such as Hounsfield unit (HU) and perviousness assessed on noncontrast computed tomography (NCCT) and CT angiography (CTA) can predict successful recanalization. We assessed whether these thrombus imaging characteristics could predict successful first-pass recanalization.Methods We retrospectively reviewed cases of mechanical thrombectomy over a three-year period in which patients received a multiphase CTA and were treated with a stent retriever on first pass. Thrombus attenuation, thrombus enhancement on arterial- and delayed-phase CTA and percentage washout were calculated and their association with first-pass recanalization, successful recanalization and distal embolic complications was studied.Results Fifty-two mechanical thrombectomy patients were included. First-pass recanalization was achieved in 59.6% and complete revascularization (Thrombolysis in Cerebral Infarction scale 2b/3) was achieved in 84.6%. There was no correlation between first-pass recanalization with thrombus density on NCCT (p= 0.94), percentage enhancement on arterial (p= 0.61) and delayed-phase CTA (p= 0.23) or thrombus length (p= 0.16). There was no correlation between number of passes and either thrombus density on NCCT (p= 0.91) or percentage enhancement on arterial- (p= 0.79) and delayed-phase (p= 0.14) CTA or thrombus length (p= 0.34). Clot length was significantly higher in patients with distal embolic complications than in those without (18.5 ± 7.9 vs 11.4 ± 6.6 mm, p= 0.005).Conclusions Our data suggest that thrombus imaging characteristics on multiphase CTA cannot predict first-pass recanalization or successful revascularization in acute ischemic stroke patients treated with stent retrievers. Longer clot length was associated with higher risk of distal embolic complications.

Background Transvenous embolisation is a promising technique but the benefits remain uncertain. We hypothesised that transvenous embolisation leads to a higher rate of arteriovenous malformation angiographic occlusion than transarterial embolisation.Methods The Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM) is an investigator initiated, multicentre, prospective, phase 2, randomised controlled clinical trial. To test the hypothesis that transvenous embolisation is superior to transarterial embolisation for arteriovenous malformation obliteration, 76 patients with arteriovenous malformations considered curable by up to two sessions of endovascular therapy will be randomly allocated 1:1 to treatment with either transvenous embolisation (with or without transarterial embolisation) (experimental arm) or transarterial embolisation alone (control arm). The primary endpoint of the trial is complete arteriovenous malformation occlusion, assessed by catheter cerebral angiography. Complete occlusions will be confirmed at 3 months, while incompletely occluded arteriovenous malformations, considered treatment failures, will then be eligible for complementary treatments by surgery, radiation therapy, or even transvenous embolisation. Standard procedural safety outcomes will also be assessed. Patient selection will be validated by a case selection committee, and participating centres with limited experience in transvenous embolisation will be proctored.Discussion The TATAM trial is a transparent research framework designed to offer a promising but still unvalidated treatment to selected arteriovenous malformation patients. Clinical Trial Registration-URL:http://www.clinicaltrials.gov. Unique identifier: NCT03691870.

There is increasing interest in venous sinus stenting in patients with idiopathic intracranial hypertension who are refractory to medical therapy. Often the transverse sinus stenoses are bilateral, however, and there is no clear evidence for whether we should stent one or both sides in these patients. Our practice is to first stent one side, and in this brief case report, we demonstrate complete resolution of the contralateral stenosis in one such patient who underwent stenting. Her symptoms also completely resolved, and so this case highlights the dynamic fluctuant nature of the transverse sinuses.

Background Intracranial dural arteriovenous fistulae (DAVF) may present a treatment challenge. Endovascular embolization is in most cases the first line of treatment but does not always achieve cure. Gamma Knife (GK) radiosurgery represents an alternative treatment option, and the purpose of this study was to further evaluate its utility.Methods We reviewed all cases of DAVF treated between 2009 and 2016 at our institution with GK radiosurgery independently, or following failed/refused endovascular or surgical management. Patients’ clinical files, radiological images, catheter angiograms, and surgical DAVF disconnection reports were retrospectively reviewed.Results Sixteen DAVF (14 patients) treated by GK radiosurgery were identified. Eleven fistulae were aggressive and five were benign. Marginal doses ranged from 15 to 25 Gy. Target volumes ranged from 0.04 to 4.47 cm3. In all symptomatic patients, GK treatment resulted in symptom palliation. In 13/15 lesions, cure of symptoms (86.0%) was reported. One lesion was asymptomatic. Angiographic cure was achieved in eight cases (50%), small residual DAVF occurred in four, and four were unchanged. One patient developed headache that resolved at one year. No hemorrhage occurred during the follow-up period. There was no significant association between Borden type and cure rate. Prior failed endovascular treatment and small target volume were associated with lower rates of cure.Conclusions Stereotactic radiosurgery is viable treatment for DAVF. It is very effective in palliating symptoms as a de novo approach or adjunctive to endovascular therapy. In our experience it is only somewhat effective in achieving complete angiographic cure.

Background Wide-necked aneurysms of the posterior communicating artery associated with a fetal posterior cerebral artery that arises from the neck or dome of the aneurysm is a clinical scenario that poses a challenge to endovascular methods.Case description A patient presented with spontaneous subarachnoid hemorrhage and was found to have a 4 × 3 × 3 mm posterior communicating artery aneurysm. Of note the aneurysm projected superiorly and a fetal posterior communicating artery aneurysm arose from the neck of the aneurysm. After multidisciplinary discussion a treatment strategy of endovascular stent-assisted coiling was chosen. Given the unique morphology of the aneurysm a novel stent-inversion maneuver was used, in which the stent was deployed from the posterior communicating artery into the distal supra-clinoid internal carotid artery. The patient tolerated the procedure well and complete aneurysm occlusion was achieved.Conclusions This case demonstrates a novel stent inversion technique that can be used for stent-assisted coiling of certain challenging aneurysms.

Developmental venous anomaly (DVA) is one of the commonest vascular malformations in the brain but rarely symptomatic. Various pathomechanisms such as mechanical compression, increased in-flow into DVA or outflow obstruction have been described as causative factors in symptomatic DVAs. We report a unique case of a pontomedullary DVA with venous outflow obstruction causing progressive neurological worsening in a young adult despite anticoagulation, who was treated with a novel approach of venous outlet stenting of the collector vein with favorable outcome. In carefully selected cases, this endovascular treatment can be an effective and safe alternative when other measures fail.

Background The natural history and outcome of unruptured posterior circulation dissecting fusiform aneurysms is not fully understood. These have a high risk of morbidity and mortality, not only due to natural history but also due to the challenging and controversial treatment approaches currently available compared to other types of intracranial aneurysms.Methods We performed a retrospective study of a prospectively collected aneurysm database at a quaternary neurovascular hospital. We included consecutive patients with unruptured intradural vertebrobasilar dissecting aneurysms between January 2000 and July 2016 who were followed to 2020. Description of baseline, procedural, and outcomes data was performed. Comparisons of patient who had aneurysm rupture on follow-up, increase in 2 or more points of mRS in follow-up and progression of the aneurysm was performed.Results Seventy patients with 78 fusiform posterior circulation aneurysms were identified. Thirty-nine (55.7%) patients were male with a mean age of 51.7 years (SD ± 17.6). When multiple, aneurysms were more likely to be fusiform (60%) than saccular (40.0%). Baseline diameter (measured on CTA/MRA/DSA), length as well as symptomatic presentation were significantly higher in aneurysms which grew over time. Coronary disease, diabetes and growth were associated an >2 increase in mRS. Diabetes as well as initial symptomatic presentation were associated with rupture.Conclusions Unruptured dissecting/fusiform aneurysm are associated with a considerable rate of rupture during follow-up. Growth is associated with morbidity even in the absence of rupture. Initial large size, coronary disease, diabetes, and to a lesser extent female gender may merit closer follow-up and/or prophylactic treatment.

Background and aim Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT.Methods Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software.Results 154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values <0.05). There were no significant differences between thrombus fragments retrieved in pass 1 and pass 2 in terms of RBC, WBC, fibrin, and platelet composition (P values >0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05).Conclusion Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.